A hydraulic cylinder includes a hollow housing with a rod/piston assembly slidably disposed within the housing. The rod includes sealing elements circumferentially disposed therearound. Sealing elements can inhibit passage or leakage of oil within the housing to the outside environment and prevent contamination from entering into the housing. The effectiveness of the sealing elements can depend on the manufacturing tolerances of not only the sealing elements but also the cylinder rod. Another factor is the surface finish after the machining process and the resultant running surface bearing ratio. The type of running surface can affect the longevity of the sealing elements and the performance of the cylinder.
There have been attempts to improve the manufacturing of the cylinder rods. For example, a cylinder stock is machined by a turning process to bring the rod to near-final size and for roundness. A grinding process can clean up any marks that are left by the turning operation and surface defects. Abrasive processes can be used for finishing the surface such as a polishing process to remove grinding lines and surface defects and a buffing process to produce a bright smooth and substantially scratchless surface. Thereafter, a chrome layer is applied to the cylinder rod. Other examples include rollers compress centerless, diamond tool lathe, and outer diameter burnishing. In one example, U.S. Patent App. Publ. 2012/0204390 describes one burnishing process. Here, a burnishing operation is performed along at least a portion of a surface of a work piece using a burnishing tool. The burnishing tool has a tool head having a rolling element supported by a bearing formed from a low coefficient of friction polymer based material. The roller element is directed across the surface of the work piece to provide a surface treatment to the surface. However, with such burnishing process it is difficult to control the roundness of the work piece. Moreover, this process and other conventional finishing processes often result in a work piece with a highly variable surface finish at a microscopic level, resulting in a less than desirable bearing ratio in the case where a sealing element is applied to work piece. In addition, such a process could introduce bending into the rod.